JP2021040455A - Charge control device - Google Patents

Abstract

To optimize a charging amount of a battery in accordance with a use state of a vehicle in a charge control device that controls the charging of a battery mounted on a vehicle.SOLUTION: A charge control device comprises: a storage unit 9 that stores a charging voltage and a termination current; a changing unit 11 that changes at least one of the charging voltage and the termination current stored in the storage unit 9; and a charging control unit 12 that gradually reduces a current flowing in a battery B when a voltage of the battery B is equal to or greater than a charging voltage stored in the storage unit 9 while the current flowing in the battery B is kept constant, and sets the current flowing in the battery B to zero when the current flowing in the battery B is equal to or smaller than the termination current stored in the storage unit 9.SELECTED DRAWING: Figure 1

Description

The present invention relates to a charge control device that controls charging of a battery mounted on a vehicle.

As a charge control device, in order to optimize the charge amount of the battery according to the usage condition of the vehicle, charging is terminated when the difference between the target charge amount and the estimated value of the current charge capacity becomes less than a fixed value. .. Patent Document 1 is a related technique.

By the way, the estimated value of the charge capacity of the battery is a value obtained from the current flowing through the battery being charged and the voltage of the battery. However, the integrated value of the current flowing through the charging battery may include an ammeter measurement error. Similarly, the measured value of the battery voltage may include a measurement error of the voltmeter.

Therefore, in the above charge control device, when charging is performed using the estimated value of the charging capacity, the estimated value does not exceed the threshold value corresponding to the overcharged state of the battery due to the influence of the error included in the estimated value. Regardless, the true charge capacity may exceed the threshold and the battery may deteriorate. Similarly, due to the influence of the error, the charge amount may be insufficient and the charge capacity may be insufficient.

Japanese Unexamined Patent Publication No. 2013-051809

An object of one aspect of the present invention is to optimize the charge amount of the battery according to the usage condition of the vehicle.

The charge control device according to the present invention is a charge control device that controls charging of a battery mounted on a vehicle, and is stored in a storage unit that stores a charge voltage and an end current, and a storage unit that stores the end current. When the changing part that changes at least one of the charging voltage and the ending current and the current flowing through the battery are kept constant and the battery voltage exceeds the charging voltage stored in the storage unit, the current flowing through the battery Is provided, and when the current flowing through the battery becomes equal to or less than the end current stored in the storage unit, the charging control unit is provided so that the current flowing through the battery becomes zero.

As a result, when the charge capacity of the battery may be relatively small, such as when the usage amount per unit time of the vehicle is small, the end current stored in the storage unit is changed to the first end current larger than the reference end current. Or change the charging voltage stored in the storage unit to a first charging voltage smaller than the reference charging voltage, or change the charging voltage stored in the storage unit to the first charging voltage and store it. By changing the end current stored in the unit to the first end current, the charging capacity of the battery after charging can be reduced, and deterioration of the battery can be suppressed. In addition, since charging is controlled using the voltage of the battery being charged and the current flowing through the battery, charging is controlled using the charging capacity estimated from the integrated value of the current flowing through the battery being charged. In comparison, it can be charged without being affected by the error included in the estimated charge capacity, it can be charged according to the amount of charge you want to charge, and the true charge capacity sets the threshold value corresponding to the overcharged state of the battery. It is possible to reduce the deterioration of the battery beyond that. Similarly, it is possible to avoid a shortage of charge capacity due to insufficient charge due to the influence of an error. That is, the charge amount of the battery can be optimized according to the usage condition of the vehicle.

Further, when the usage amount per unit time of the vehicle is equal to or less than the first threshold value and is larger than the second threshold value smaller than the first threshold value, the changing unit stores the end current stored in the storage unit. When the end current is changed to 1 and the usage amount per unit time of the vehicle is equal to or less than the second threshold value and larger than the third threshold value smaller than the second threshold value, the charging voltage stored in the storage unit is stored. Is changed to the first charging voltage, and when the usage amount per unit time of the vehicle is equal to or less than the third threshold value, the charging voltage stored in the storage unit is changed to the first charging voltage and stored in the storage unit. The stored end current may be changed to the first end current.

As a result, when the time available for charging the vehicle is short and the vehicle is used immediately after the charging is completed, the end current stored in the storage unit is changed to the first end current. Since it is possible to suppress the decrease in the charge capacity of the battery after charging, it is possible to extend the life of the battery while ensuring the charge capacity of the battery. Further, when the time that the vehicle can devote to charging is short, and the usage amount per unit time of the vehicle is relatively small, or when the vehicle is left for a relatively long time after the charging is completed, it is stored in the storage unit. By changing the charging voltage to the first charging voltage, the charging capacity of the battery after charging can be reduced, so that the life of the battery can be extended. By the way, the accuracy of the charge amount can be ensured by changing the charging voltage, and the charge amount per hour can be secured by changing the charging current. Therefore, when the usage amount per unit time of the vehicle is smaller or when the vehicle is left for a longer time after charging is completed, the charging voltage stored in the storage unit is changed to the first charging voltage and stored in the storage unit. By combining the respective methods so as to change the stored end current to the first end current, it is possible to achieve both a long battery life and an optimum charge capacity.

Further, the changing unit changes the end current stored in the storage unit to a second end current that is larger than the reference end current and smaller than the first end current, depending on the temperature of the battery or the degree of deterioration of the battery. Alternatively, the charging voltage stored in the storage unit is changed to a second charging voltage that is smaller than the reference charging voltage and larger than the first charging voltage, or the charging voltage stored in the storage unit is changed. The end current stored in the storage unit may be changed to the second end current while changing to the second charging voltage.

As a result, even if the internal resistance of the battery increases as the temperature of the battery decreases or the battery deteriorates and the voltage of the battery being charged increases, it is possible to suppress a decrease in the charge amount of the battery. It is possible to suppress a decrease in the mileage and operating time of the vehicle due to the temperature rise and deterioration of the battery.

Further, the charge control device according to the present invention is a charge control device that controls the charge of the battery mounted on the vehicle, and is stored in a storage unit that stores the charge voltage and a storage unit. A change unit that changes the charging voltage, and a charge control unit that makes the current flowing through the battery zero when the battery voltage exceeds the charging voltage stored in the storage unit when the current flowing through the battery is constant. To be equipped.

As a result, when the charge capacity of the battery may be relatively small, such as when the usage amount per unit time of the vehicle is small, the charge voltage stored in the storage unit is changed to the first charge voltage smaller than the reference charge voltage. By doing so, the amount of charge of the battery after charging can be reduced, and deterioration of the battery can be suppressed. Further, since the charging is controlled by using the voltage of the battery being charged, the ammeter is compared with the case where the charging is controlled by using the charging capacity estimated by the integrated value of the current flowing through the battery being charged. The charge capacity of the battery after charging can be brought closer to the true charge capacity by eliminating the influence of the measurement error of, and the true charge capacity exceeds the threshold value corresponding to the overcharged state of the battery and the battery deteriorates. Can be reduced. That is, the charge capacity of the battery can be optimized according to the usage status of the vehicle.

Further, the changing unit changes the charging voltage stored in the storage unit to a second charging voltage that is smaller than the reference charging voltage and larger than the first charging voltage, depending on the temperature of the battery or the degree of deterioration of the battery. You may try to do it.

As a result, even if the internal resistance of the battery increases as the temperature of the battery rises or the battery deteriorates and the voltage of the battery being charged increases, the voltage of the battery is unlikely to exceed the charging voltage stored in the storage unit. Therefore, it is possible to suppress a decrease in the charge amount of the battery, and it is possible to suppress a decrease in the mileage and the mileage of the vehicle due to the temperature rise of the battery and the deterioration of the battery.

According to the present invention, the charge amount of the battery can be optimized according to the usage condition of the vehicle.

It is a figure which shows an example of the vehicle which includes the charge control device of embodiment, and a charger. It is a figure which shows an example of a screen. It is a flowchart which shows an example of the operation of a control part. It is a figure which shows an example of the current flowing through a battery and the voltage of a battery. It is a figure which shows an example of the current flowing through a battery and the voltage of a battery.

Hereinafter, embodiments will be described in detail based on the drawings.
FIG. 1 is a diagram showing an example of a vehicle and a charger including the charge control device of the embodiment.

The vehicle Ve shown in FIG. 1 is an electric forklift, an electric towing tractor, an electric vehicle, or the like, and includes a load Lo, a storage unit 1, a control unit 2, and a battery pack BP.

The load Lo is an inverter circuit or the like that drives a traveling motor or a cargo handling motor.
The storage unit 1 is composed of a RAM (Random Access Memory), a ROM (Read Only Memory), or the like.

The control unit 2 is composed of a CPU (Central Processing Unit) or a programmable device (FPGA (Field Programmable Gate Array) or PLD (Programmable Logic Device)), and controls the operation of the load Lo and the overall operation of the vehicle Ve. ..

The charger Ch includes a power conversion unit 3, a storage unit 4, and a control unit 5.
The power conversion unit 3 converts the AC power supplied from the system power supply P into a predetermined power and supplies it to the battery pack BP.

The storage unit 4 is composed of a RAM, a ROM, or the like.
The control unit 5 is composed of a CPU, a programmable device, or the like, and controls the operation of the power conversion unit 3 based on an instruction from the user or an instruction from the vehicle Ve.

The battery pack BP includes a battery B, a voltmeter 6, an ammeter 7, a thermometer 8, a switch SW1, a switch SW2, a storage unit 9, and a control unit 10.

The battery B is composed of one or more secondary batteries such as a lithium ion battery or a nickel hydrogen battery, and supplies electric power to the load Lo. Further, when power is supplied to the battery B from the charger Ch provided outside the vehicle Ve, that is, when a current is flowing from the charger Ch to the battery B, the battery B is charged and the voltage of the battery B is increased. Rise.

The voltmeter 6 is composed of a voltage dividing resistor, an operational amplifier, or the like, measures the voltage of the battery B, and sends the measured voltage to the control unit 10.

The ammeter 7 is composed of a Hall element, a shunt resistor, or the like, measures the current flowing through the battery B, and sends the measured current to the control unit 10.

The thermometer 8 is composed of a thermistor or the like, measures the temperature of the battery B, and sends the measured temperature to the control unit 10.

The switches SW1 and SW2 are each composed of a semiconductor relay (for example, MOSFET (Metal Oxide Semiconductor Field Effect Transistor)) or an electromagnetic relay. One terminal of the switch SW1 is connected to the negative terminal of the battery B, and the other terminal of the switch SW1 is connected to the negative terminal of the charger Ch. One terminal of the switch SW2 is connected to the negative terminal of the battery B, and the other terminal of the switch SW2 is connected to the negative terminal of the load Lo. When the switch SW1 becomes conductive and the switch SW2 shuts off, it becomes possible to supply electric power to the battery B from the charger Ch. Further, when the switch SW1 is cut off and the switch SW2 is electrically connected, the battery B can supply electric power to the load Lo.

The storage unit 9 is composed of a RAM, a ROM, or the like, and stores a charging voltage and an end current, which will be described later. It is assumed that the reference charging voltage Vr and the reference end current Ir are stored in the storage unit 9 as initial values.

The control unit 10 is composed of a CPU, a programmable device, or the like, includes a change unit 11 and a charge control unit 12, and controls the operations of the switches SW1 and SW2. Further, the control unit 10 communicates with the control unit 2 and the control unit 5. The changing unit 11 and the charging control unit 12 are realized by the CPU or the programmable device executing the program stored in the storage unit 9. For example, the charge control device includes a storage unit 9, a change unit 11 of the control unit 10, and a charge control unit 12 of the control unit 10. The changing unit 11 and the charging control unit 12 may be provided in the control unit 2 mounted on the vehicle Ve. In this configuration, the charge control device is composed of a storage unit 1, a change unit 11 of the control unit 2, and a charge control unit 12 of the control unit 2. Further, the changing unit 11 and the charging control unit 12 may be provided in the control unit 5 mounted on the charger Ch. In this configuration, the charge control device is composed of a storage unit 4, a change unit 11 of the control unit 5, and a charge control unit 12 of the control unit 5.

The changing unit 11 changes at least one of the charging voltage and the ending current stored in the storage unit 9. Further, after changing at least one of the charging voltage and the end current stored in the storage unit 9, the changing unit 11 further changes the temperature of the battery B or the degree of deterioration of the battery B (internal resistance of the battery B or the like). At least one of the charging voltage and the ending current stored in the storage unit 9 is changed according to the full charge capacity, etc.).

The charge control unit 12 performs constant current charge control and constant voltage charge control using the charge voltage and end current stored in the storage unit 9.

First, the charge control unit 12 instructs the control unit 5 of the charger Ch so that the current measured by the ammeter 7 becomes constant when the constant current charge control is started. The control unit 5 controls the operation of the power conversion unit 3 so that the current flowing from the charger Ch to the battery B becomes constant according to the instruction. When a constant current is flowing through the battery B, the battery B is charged and the voltage of the battery B gradually rises.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage stored in the storage unit 9, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. When the charge control unit 14 starts the constant voltage charge control, the current flowing from the charger Ch to the battery B gradually decreases while maintaining the state in which the voltage of the battery B is equal to or higher than the charge voltage stored in the storage unit 9. The control unit 5 is instructed to do so. According to the instruction, the control unit 5 powers the battery B so that the current flowing from the charger Ch to the battery B gradually decreases while maintaining the state where the voltage of the battery B is equal to or higher than the charging voltage stored in the storage unit 9. Controls the operation of the conversion unit 3. For example, in the control unit 5, the current measured by the ammeter 7 is set to a predetermined value each time the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage stored in the storage unit 9 during constant voltage charge control. It may be configured to control the operation of the power conversion unit 3 so as to reduce the voltage.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current stored in the storage unit 9, the charge control unit 12 controls the control unit 5 so that the current flowing from the charger Ch to the battery B becomes zero. Is instructed to end the constant voltage charging control.

<Example 1 of change unit 11>
The change unit 11 stores the storage unit 9 when the charge capacity of the battery B may be relatively small, such as when the usage amount per unit time of the vehicle Ve (travel distance, travel time, etc. per unit time of the vehicle Ve) is small. The end current stored in is changed to the end current I1 (first end current) larger than the reference end current Ir, or the charge voltage stored in the storage unit 9 is changed to the charge voltage V1 smaller than the reference charge voltage Vr. The charging voltage is changed to (first charging voltage), or the charging voltage stored in the storage unit 9 is changed to the charging voltage V1 and the end current stored in the storage unit 9 is changed to the end current I1. As a result, the charge capacity of the battery B after charging can be reduced, so that deterioration of the battery B can be suppressed and the life of the battery B can be extended.

<Example 2 of change unit 11>
When the usage amount of the vehicle Ve per unit time is equal to or less than the first threshold value and larger than the second threshold value, the change unit 11 changes the end current stored in the storage unit 9 to the end current I1. When the usage amount of the vehicle Ve per unit time is equal to or less than the second threshold value and larger than the third threshold value, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1 of the vehicle Ve. When the usage amount per unit time is equal to or less than the third threshold value, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1 and the end current stored in the storage unit 9 is changed to the end current I1. To do. The first threshold value> the second threshold value> the third threshold value. As a result, when the vehicle Ve is an industrial vehicle such as a forklift, the battery B is charged in a relatively short charging time, and the vehicle Ve is used immediately after the charging is completed, the storage unit. By changing the end current stored in 9 to the end current I1, the decrease in the charge capacity of the battery B after charging can be suppressed, so that the length of the battery B can be secured while ensuring the charge capacity of the battery B. The life can be extended. Further, when the vehicle Ve is an industrial vehicle such as a forklift and the usage amount of the vehicle Ve per unit time is relatively small, or when the vehicle Ve is left for a relatively long time after charging is completed, the storage unit 9 By changing the charging voltage stored in the battery B to the charging voltage V1, the charging capacity of the battery B after charging can be reduced, so that the life of the battery B can be extended. Further, when the vehicle Ve is an industrial vehicle such as a forklift, and the usage amount of the vehicle Ve per unit time is smaller, or when the vehicle Ve is left for a longer time after the charging is completed, the vehicle Ve is stored in the storage unit 9. By changing the charging voltage to the charging voltage V1 and the end current stored in the storage unit 9 to the end current I1, the charging capacity of the battery B after charging can be further reduced. The life of the battery B can be further extended.

<Example 3 of change unit 11>
The change unit 11 is from a user who wants to extend the life of the battery B while charging the battery B in a relatively short time, or a user who wants to extend the life of the battery B because the usage amount of the vehicle Ve per unit time is relatively small. According to the instruction, the end current stored in the storage unit 9 is changed to the end current I1, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1, or the end current is stored in the storage unit 9. The charging voltage is changed to the charging voltage V1 and the end current stored in the storage unit 9 is changed to the end current I1.

Here, FIGS. 2A and 2B are diagrams showing an example of a screen displayed on a display unit (touch panel or the like) (not shown) provided in the battery pack Bp, the vehicle Ve, or the charger Ch. is there.

Buttons B1 to B4 are provided on the screen D1 shown in FIG. 2A.
When the user presses the button B1 and an instruction to the effect that "normal mode" is selected is input to the changing unit 11, the changing unit 11 does not change the charging voltage and the ending current stored in the storage unit 9. .. That is, when the "normal mode" is selected by the user, the charging voltage and the end current stored in the storage unit 9 are not changed as the reference charging voltage Vr and the reference end current Ir.

When the user presses the button B2 and an instruction indicating that the "supplementary charging mode" is selected is input to the changing unit 11, the changing unit 11 does not change the charging voltage stored in the storage unit 9 and stores it. The end current stored in unit 9 is changed to the end current I1. That is, when the "supplementary charging mode" is selected by the user, the charging voltage stored in the storage unit 9 is not changed as the reference charging voltage Vr, and the end current stored in the storage unit 9 becomes large.

When the user presses the button B3 and an instruction indicating that "life extension mode A" is selected is input to the changing unit 11, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1. At the same time, the end current stored in the storage unit 9 is not changed. That is, when the "life extension mode A" is selected by the user, the charging voltage stored in the storage unit 9 becomes smaller, and the end current stored in the storage unit 9 is not changed as the reference end current Ir.

When the user presses the button B4 and an instruction indicating that "life extension mode B" is selected is input to the changing unit 11, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1. At the same time, the end current stored in the storage unit 9 is changed to the end current I1. That is, when the "life extension mode B" is selected by the user, the charging voltage stored in the storage unit 9 becomes smaller and the end current stored in the storage unit 9 becomes larger.

On the screen D2 shown in FIG. 2B, buttons Bv1 to Bv8 for changing the charging voltage stored in the storage unit 9 in eight stages and the end current stored in the storage unit 9 in eight stages are displayed. Buttons Bi1 to Bi8 for changing are provided. The button Bv1 corresponds to the charging voltage V1, and the button Bv8 corresponds to the reference charging voltage Vr. Further, the charging voltage corresponding to each button increases in the order of buttons Bv2, Bv3, Bv4, Bv5, Bv6, and Bv7. Further, the button Bi1 corresponds to the reference end current Ir, and the button Bi8 corresponds to the end current I1. Further, the end current corresponding to each button increases in the order of buttons Bi2, Bi3, Bi4, Bi5, Bi6, and Bi7.

When the button Bv8 is pressed and the button Bi1 is pressed by the user, the changing unit 11 does not change the charging voltage and the ending current stored in the storage unit 9. That is, when the button Bv8 is pressed and the button Bi1 is pressed by the user, the charging voltage and the end current stored in the storage unit 9 are not changed as the reference charging voltage Vr and the reference end current Ir.

When the button Bv8 is pressed and the button Bi8 is pressed by the user, the changing unit 11 does not change the charging voltage stored in the storage unit 9 and changes the ending current stored in the storage unit 9 to the ending current I1. To do. That is, when the button Bv8 is pressed and the button Bi8 is pressed by the user, the charging voltage stored in the storage unit 9 is not changed as the reference charging voltage Vr, and the end current stored in the storage unit 9 is large. Become.

When the button Bv1 is pressed and the button Bi1 is pressed by the user, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1 and changes the end current stored in the storage unit 9. do not do. That is, when the button Bv1 is pressed and the button Bi1 is pressed by the user, the charging voltage stored in the storage unit 9 becomes smaller and the end current stored in the storage unit 9 is changed to the reference end current Ir. Not done.

When the button Bv1 is pressed and the button Bi8 is pressed by the user, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V1 and ends the end current stored in the storage unit 9. Change to current I1. That is, when the button Bv1 is pressed and the button Bi8 is pressed by the user, the charging voltage stored in the storage unit 9 becomes smaller and the end current stored in the storage unit 9 becomes larger.

<Example 4 of change unit 11>
The change unit 11 sets the end current stored in the storage unit 9 to be larger than the reference end current Ir and smaller than the end current I1 according to the temperature of the battery B or the degree of deterioration of the battery B (second). Change to (end current). Further, the changing unit 11 sets the charging voltage stored in the storage unit 9 to be smaller than the reference charging voltage Vr and larger than the charging voltage V1 according to the temperature of the battery B or the degree of deterioration of the battery B (the charging voltage V2 ( Change to the second charging voltage). Further, the changing unit 11 changes the charging voltage stored in the storage unit 9 to the charging voltage V2 and changes the end current stored in the storage unit 9 according to the temperature of the battery B or the degree of deterioration of the battery B. Change to the end current I2. As a result, even if the internal resistance of the battery B increases due to the temperature rise of the battery B or the deterioration of the battery B and the voltage of the battery B during charging increases, it is possible to suppress the decrease in the charging capacity of the battery B. Therefore, it is possible to prevent the mileage of the vehicle Ve from decreasing due to the temperature rise of the battery B and the deterioration of the battery B.

FIG. 3 is a flowchart showing an example of the operation of the control unit 10.
First, the changing unit 11 of the control unit 10 changes the charging voltage and the end current stored in the storage unit 9 according to the usage status of the vehicle Ve, the instruction from the user, the temperature of the battery B, or the deterioration of the battery B. At least one of them is changed (step S1).

Next, the charge control unit 12 of the control unit 10 performs constant current charge control and constant voltage charge control using the charge voltage and end current stored in the storage unit 9 (steps S2 to S5).

First, the charge control unit 12 starts constant current charge control (step S2), and when the voltage measured by the voltmeter 6 is smaller than the charge voltage stored in the storage unit 9 (step S3: No), The constant current charge control is continuously performed (step S2).

On the other hand, when the voltage measured by the voltmeter 6 is equal to or higher than the charging voltage stored in the storage unit 9 (step S3: Yes), the charging control unit 12 ends the constant current charging control and charges the constant voltage. Control is started (step S4).

Next, when the current measured by the ammeter 7 is larger than the end current stored in the storage unit 9 (step S5: No), the charge control unit 12 continues the constant voltage charge control (step). S4).

On the other hand, when the current measured by the ammeter 7 is equal to or less than the end current stored in the storage unit 9 (step S5: Yes), the charge control unit 12 ends the constant current charge control.

Here, FIGS. 4 and 5 are diagrams showing an example of the current flowing through the battery B and the voltage of the battery B when the constant current charge control and the constant voltage charge control are performed.

FIG. 4A shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the reference ending current Ir. Further, FIG. 4B shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I1. Further, FIG. 4C shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the reference ending current Ir. Further, FIG. 4D shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the ending current I1. Further, the horizontal axis of the two-dimensional coordinates shown in FIGS. 4 (a) to 4 (d) indicates time, and the vertical axis indicates current or voltage. The solid line shown in FIGS. 4 (a) to 4 (d) indicates the current measured by the ammeter 7, and the broken line shown in FIGS. 4 (a) to 4 (d) is measured by the voltmeter 6. Indicates the voltage to be applied.

(When the charging voltage and the end current stored in the storage unit 9 are the reference charging voltage Vr and the reference end current Ir)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 4 (a). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the reference charging voltage Vr at time t3 in FIG. 4A, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. Then, the current measured by the ammeter 7 is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the reference end current Ir at the time t6 of FIG. 4A, the charge control unit 12 sets the current measured by the ammeter 7 to zero. End the voltage charge control.

(When the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I1)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 4B. Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the reference charging voltage Vr at time t3 in FIG. 4B, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. Then, the current measured by the ammeter 7 is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I1 at the time t4 in FIG. 4B, the charge control unit 12 sets the current measured by the ammeter 7 to zero to a constant voltage. End charge control.

(When the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the reference ending current Ir)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 4 (c). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage V1 at the time t1 in FIG. 4C, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. , The current measured by the ammeter 7 is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the reference end current Ir at the time t5 in FIG. 4 (c), the charge control unit 12 sets the current measured by the ammeter 7 to zero. End the voltage charge control.

(When the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the ending current I1)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 4 (d). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the charging voltage V1 at the time t1 in FIG. 4D, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. , The current measured by the ammeter 7 is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I1 at the time t2 in FIG. 4D, the charge control unit 12 sets the current measured by the ammeter 7 to zero to a constant voltage. End charge control.

It should be noted that time t0 <time t1 <time t2 <time t3 <time t4 <time t5 <time t6. Further, the period from time t3 to time t6 and the period from time t1 to time t5 are the same as each other.

In this case, the integrated value (charge amount) of the current flowing through the battery B during the period from time t3 to time t4 is smaller than the integrated value of the current flowing through the battery B during the period from time t3 to time t6.

Therefore, when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I1, the charging capacity of the battery B at the end of charging is the charging voltage and the charging capacity stored in the storage unit 9. When the end current is the reference charge voltage Vr and the reference end current Ir, it becomes smaller than the charge capacity of the battery B at the end of charging.

That is, when only the end current is increased, the charge capacity of the battery B can be reduced and the life of the battery B can be extended as compared with the case where the charging voltage and the end current are not changed.

Further, the integrated value of the current flowing through the battery B during the period from time t3 to time t6 and the integrated value of the current flowing through the battery B during the period from time t1 to time t5 are the same as each other. The integrated value of the current flowing through the battery B during the period from time t0 to time t1 is smaller than the integrated value of the current flowing through the battery B during the period from time t0 to time t3.

Therefore, when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the reference end current Ir, the charging capacity of the battery B at the end of charging is the charging voltage and the charging capacity stored in the storage unit 9. When the end current is the reference charge voltage Vr and the reference end current Ir, it becomes smaller than the charge capacity of the battery B at the end of charging.

That is, when only the charging voltage is reduced, the charging capacity of the battery B can be reduced and the life of the battery B can be extended as compared with the case where the charging voltage and the end current are not changed. When only the end current is increased, the charging time can be shortened while securing the charging capacity as compared with the case where only the charging voltage is decreased.

Further, the integrated value of the current flowing through the battery B during the period from time t1 to time t2 is smaller than the integrated value of the current flowing through the battery B during the period from time t1 to time t5.

Therefore, when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the ending current I1, the charging capacity of the battery B at the end of charging is the charging voltage and the ending current stored in the storage unit 9. When the current is the charging voltage V1 and the reference end current Ir, it becomes smaller than the charge capacity of the battery B at the end of charging.

That is, when the charging voltage is reduced and the end current is increased, the charging capacity of the battery B can be further reduced as compared with the case where only the charging voltage is decreased, so that the battery life can be extended and the optimum charging capacity can be increased. It is possible to secure both.

Further, FIG. 5A shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I2. Further, FIG. 5B shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the reference ending current Ir. Further, FIG. 5C shows the current flowing through the battery B and the voltage of the battery B when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the ending current I2. Further, the horizontal axis of the two-dimensional coordinates shown in FIGS. 5 (a) to 5 (c) indicates time, and the vertical axis indicates current or voltage. The solid line shown in FIGS. 5 (a) to 5 (c) indicates the current measured by the ammeter 7, and the broken line shown in FIGS. 5 (a) to 5 (c) is measured by the voltmeter 6. Indicates the voltage to be applied.

(When the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I2)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 5 (a). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes equal to or higher than the reference charging voltage Vr at time t3 in FIG. 5A, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. Then, the current measured by the ammeter 7 is gradually reduced.

Then, at the time t4'in FIG. 5A, the charge control unit 12 sets the current measured by the ammeter 7 to zero when the current measured by the ammeter 7 becomes equal to or less than the end current I2. End the voltage charge control.

(When the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the reference ending current Ir)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 5 (b). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes the charging voltage V2 or higher at the time t1'in FIG. 5B, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. Then, the current flowing through the battery B is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the reference end current Ir at the time t5'in FIG. 5B, the charge control unit 12 sets the current flowing through the battery B to zero and charges the battery at a constant voltage. End control.

(When the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the ending current I2)
First, the charge control unit 12 starts constant current charge control at time t0 in FIG. 5 (c). Then, the current measured by the ammeter 7 becomes a constant current Ic, and the voltage measured by the voltmeter 6 gradually increases.

Next, when the voltage measured by the voltmeter 6 becomes the charging voltage V2 or higher at the time t11 in FIG. 5C, the charging control unit 12 ends the constant current charging control and starts the constant voltage charging control. , The current flowing through the battery B is gradually reduced.

Then, when the current measured by the ammeter 7 becomes equal to or less than the end current I2 at the time t22 in FIG. 5C, the charge control unit 12 sets the current measured by the ammeter 7 to zero to a constant voltage. End charge control.

The period from time t3 to time t4'shown in FIG. 5 (a) is longer than the period from time t3 to time t4 shown in FIG. 4 (b). Further, the period from time t0 to time t1'shown in FIG. 5 (b) is longer than the period from time t0 to time t1 shown in FIG. 4 (c). Further, the period from time t1'to time t5'shown in FIG. 5B and the period from time t1 to time t5 shown in FIG. 4C are assumed to be the same as each other. Further, the period from time t0 to time t11 shown in FIG. 5 (c) is longer than the period from time t0 to time t1 shown in FIG. 4 (d). Further, the period from time t11 to time t22 shown in FIG. 5 (c) is longer than the period from time t1 to time t2 shown in FIG. 4 (d).

In this case, the integrated value of the current flowing through the battery B during the period from time t3 to time t4'shown in FIG. 5A flows through the battery B during the period from time t3 to time t4 shown in FIG. 4B. It becomes larger than the integrated value of the current.

Therefore, when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I2, the charging capacity of the battery B at the end of charging is the charging voltage and the charging capacity stored in the storage unit 9. When the end current is the reference charging voltage Vr and the end current I1, it becomes larger than the charge capacity of the battery B at the end of charging.

That is, when the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I2, the charging voltage and the ending current stored in the storage unit 9 are the reference charging voltage Vr and the ending current I1. Compared with the case where, the mileage and the traveling time of the vehicle Ve can be extended.

Further, the integrated value of the current flowing through the battery B during the period from time t1'to time t5'shown in FIG. 5 (b) flows through the battery B during the period from time t1 to time t5 shown in FIG. 4 (c). It becomes the same as the integrated value of the current. The integrated value of the current flowing through the battery B during the period from time t0 to time t1'shown in FIG. 5 (b) is the integrated value of the current flowing through the battery B during the period from time t0 to time t1 shown in FIG. 4 (c). Greater than the value.

Therefore, when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the reference end current Ir, the charging capacity of the battery B at the end of charging is the charging voltage and the charging capacity stored in the storage unit 9. When the end current is the charging voltage V1 and the reference end current Ir, it becomes larger than the charge capacity of the battery B at the end of charging.

That is, when the charging voltage and the end current stored in the storage unit 9 are the charging voltage V2 and the reference end current Ir, the charging voltage and the end current stored in the storage unit 9 are the charging voltage V1 and the reference end current Ir. Compared with the case where, the mileage and the traveling time of the vehicle Ve can be extended.

Further, the integrated value of the current flowing through the battery B during the period from time t0 to time t11 shown in FIG. 5 (c) is the integrated value of the current flowing through the battery B during the period from time t0 to time t1 shown in FIG. 4 (d). It becomes larger than the integrated value. The integrated value of the current flowing through the battery B during the period from time t11 to time t22 shown in FIG. 5 (c) is the integrated value of the current flowing through the battery B during the period from time t1 to time t2 shown in FIG. 4 (d). Become larger.

Therefore, when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the ending current I2, the charging capacity of the battery B at the end of charging is the charging voltage and the ending current stored in the storage unit 9. When the current is the charging voltage V1 and the ending current I1, it becomes larger than the charging capacity of the battery B at the end of charging.

That is, when the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V2 and the ending current I2, the charging voltage and the ending current stored in the storage unit 9 are the charging voltage V1 and the ending current I1. Compared with the case, the mileage and the traveling time of the vehicle Ve can be extended.

As described above, in the charge control device of the embodiment, when the charge capacity of the battery B may be relatively small, such as when the usage amount of the vehicle Ve per unit time is small, the end current stored in the storage unit 9 is stored. The end current is changed to I1, the charging voltage stored in the storage unit 9 is changed to the charging voltage V1, or the charging voltage stored in the storage unit 9 is changed to the charging voltage V1 and the storage unit 9 is used. The end current stored in is changed to the end current I1. As a result, the charging capacity of the battery B after charging can be reduced, and deterioration of the battery B can be suppressed. Further, since the charging is controlled by using the voltage of the battery B being charged and the current flowing through the battery B, the charging is controlled by using the charging capacity estimated by the integrated value of the current flowing through the battery B being charged. The effect of the measurement error of the current meter 7 can be reduced and the charge capacity of the battery B after charging can be brought closer to the true charge capacity, and the true charge capacity corresponds to the overcharged state of the battery B. It is possible to reduce the deterioration of the battery B beyond the threshold value. That is, the charge amount of the battery B can be optimized according to the usage status of the vehicle Ve.

Further, the present invention is not limited to the above embodiments, and various improvements and changes can be made without departing from the gist of the present invention.

<Modification example>
In the above embodiment, the battery B is charged by performing the constant current voltage control and the constant voltage charging control, but the battery B may be charged by performing only the constant current charging control.

In this configuration, the storage unit 9 stores the charging voltage. Further, the changing unit 11 changes the charging voltage stored in the storage unit 9. Further, the charge control unit 12 flows to the battery B when the voltage of the battery B becomes equal to or higher than the charge voltage stored in the storage unit 9 when the current flowing through the battery B is kept constant during the constant current charge control. Make the current zero.

The changing unit 11 may be configured to change the charging voltage stored in the storage unit 9 to the charging voltage V1 according to the usage status of the vehicle Ve and the instruction from the user. As a result, the charging capacity of the battery B after charging can be reduced, and deterioration of the battery B can be suppressed. Further, since the charging is controlled by using the voltage of the battery B being charged, the charging is controlled by using the charging capacity estimated by the integrated value of the current flowing through the battery B being charged. The charge capacity of the battery B after charging can be brought closer to the true charge capacity by eliminating the influence of the measurement error of the ammeter 7, and the true charge capacity exceeds the threshold value corresponding to the overcharge state of the battery B. Can be reduced from deterioration. That is, the charge amount of the battery B can be optimized according to the usage status of the vehicle Ve.

Further, the changing unit 11 may be configured to change the charging voltage stored in the storage unit 9 to the charging voltage V2 according to the temperature of the battery B or the degree of deterioration of the battery B. As a result, even if the internal resistance of the battery B increases as the temperature of the battery B rises or the battery B deteriorates and the voltage of the battery B being charged increases, the voltage of the battery B is stored in the storage unit 9. Since it can be made difficult to exceed the charging voltage, it is possible to suppress a decrease in the charging capacity of the battery B, and the mileage and running time of the vehicle Ve as the temperature of the battery B rises and the battery B deteriorates. It can be suppressed from decreasing.

1 Storage unit 2 Control unit 3 Power conversion unit 4 Storage unit 5 Control unit 6 Voltmeter 7 Ammeter 8 Thermometer 9 Storage unit 10 Control unit 11 Change unit 12 Charge control unit

Claims (7)

A charge control device that controls the charging of batteries installed in vehicles.
A storage unit that stores the charging voltage and end current,
A change unit that changes at least one of the charging voltage and the end current stored in the storage unit, and
When the current flowing through the battery is kept constant and the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit, the current flowing through the battery is gradually reduced, and the current flowing through the battery becomes the current flowing through the battery. A charge control unit that reduces the current flowing through the battery to zero when the current falls below the end current stored in the storage unit.
Charge control device equipped with. The charge control device according to claim 1.
The changing unit changes the end current stored in the storage unit to a first end current larger than the reference end current, or charges stored in the storage unit, depending on the usage status of the vehicle. The voltage is changed to a first charging voltage smaller than the reference charging voltage, or the charging voltage stored in the storage unit is changed to the first charging voltage, and the end current stored in the storage unit is changed. A charge control device characterized by changing to the first end current. The charge control device according to claim 1.
When the usage amount of the vehicle per unit time is equal to or less than the first threshold value and is larger than the second threshold value smaller than the first threshold value, the change unit stores the end current stored in the storage unit. Is changed to a first end current larger than the reference end current, and the usage amount of the vehicle per unit time is equal to or less than the second threshold value and larger than the third threshold value smaller than the second threshold value. When the charging voltage stored in the storage unit is changed to a first charging voltage smaller than the reference charging voltage and the usage amount of the vehicle per unit time is equal to or less than the third threshold value, the storage unit stores the charging voltage. A charge control device characterized in that the stored charging voltage is changed to the first charging voltage and the end current stored in the storage unit is changed to the first end current. The charge control device according to claim 2 or 3.
The change unit has a second end current stored in the storage unit, which is larger than the reference end current and smaller than the first end current, depending on the temperature of the battery or the degree of deterioration of the battery. The charging voltage is changed to the end current, or the charging voltage stored in the storage unit is changed to a second charging voltage that is smaller than the reference charging voltage and larger than the first charging voltage, or the storage unit. A charging control device characterized in that the charging voltage stored in is changed to the second charging voltage and the end current stored in the storage unit is changed to the second ending current. A charge control device that controls the charging of batteries installed in vehicles.
A storage unit that stores the charging voltage and
A changing unit that changes the charging voltage stored in the storage unit,
When the voltage of the battery becomes equal to or higher than the charging voltage stored in the storage unit when the current flowing through the battery is kept constant, the charging control unit that makes the current flowing through the battery zero.
Charge control device equipped with. The charge control device according to claim 5.
The changing unit is a charging control device characterized in that the charging voltage stored in the storage unit is changed to a first charging voltage smaller than the reference charging voltage according to the usage status of the vehicle. The charge control device according to claim 6.
The changing unit has a second charging voltage stored in the storage unit, which is smaller than the reference charging voltage and larger than the first charging voltage, depending on the temperature of the battery or the degree of deterioration of the battery. A charge control device characterized by changing to a charge voltage.

Images